(a) Technical Field
The present invention relates to an information display system for a vehicle. More particularly, the present invention relates to an information display system for a vehicle, which can display a panoramic view image showing the surrounding area of the vehicle along with a vehicle's image overlapped thereon.
(b) Background Art
Japanese unexamined patent application No. H11-78692 discloses a method of providing visual information with a driver, in which images of surrounding circumstance of a vehicle are taken by a plurality of cameras installed on the vehicle; the obtained images are processed to form a single surrounding image, a composite image having a virtual viewpoint from top of the vehicle is prepared; and the composite image is displayed on a display means equipped in the vehicle.
Such a method may not be suitable for providing sufficient visual information on circumstance while driving, since the viewpoint from top is restricted to very limited area.
Japanese unexamined patent publication No. 2007-158426 discloses a device for displaying the surrounding area of a vehicle. The device serves to form a single panoramic view image by combining a plurality of surrounding images and then overlaying an image of said vehicle onto the panoramic view image. The clarity of the object in the image varies depending on a distance between the object and the own vehicle.
The device adopts a virtual viewpoint from a rear side of the vehicle so that the displayed image also has a rear side viewpoint. Since such an image has a different viewpoint compared with an image which a driver really perceives through a windshield, the driver may experience confusion in determining the circumstance or information displayed on the device.
A solid image recognition method, in which the image is taken by a plurality of cameras and a distance to an object is calculated; a method of compensating distortion caused by a lens; and a image recognition method are disclosed in a non-patent material (“Solid image recognition” Tokyo industrial university, radio-isotope laboratory, saneyoshi lab. homepage, publicly available on the world wide web at ric.titech.ac.jp/saneken//stereocamera.htm.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.